Manufacture of filaments and films from viscose.



UNITED s'rArns PATENT- OFFICE.

UI IARLES N. WAITE, OF LANSDOWNE, PENNSYLVANIA, ASSIGNOR, BY MESNE I ASSlG NMENTS, TO SILAS W. PETTIT, OF PHILADELPHIA, PENNSYLVANIA.

MANUFACTURE OF FILAMENTS ANYD FILMS FROM vlscoss;

Patented April 9, 1907.

Application filed May 1904. Serial No. 206,174.

T0 all whom, it may concern:

Be it known that I, CHARLES N. WAITE, of

Lansdowne, in the county of'Delaware and State of Pennsylvania, have invented certain new and useful Improvements in the filaments thus produced are set in the form given to them by the spinnerets.

Heretofore either an ammonium salt such as ammonium chlorid or ammonium sulfid or sulfuric acidh as been employed as the efficient agent of the setting-bath. I have found that when either ammonium salt aforesaid is used ammonium sulfid is liberated in, I large quantities and sulfur effloresces on the filaments, impairing their luster and rendering their color objectionable. I have also found that if sulfuric acid is used in aqueous solution hydrogen sulfid is liberated, with the disadvantages which are due to the presence of that poisonous gas, and

sulfur is also deposited in the filaments.

The usual method of finally treating such roducts intended to eliminate any remain-' consisting of sodium bisulfite, (NaHSO into which the filaments or films are projected, with the result that the sodium-hydrate in-the viscose is'neutralized and the.

sulfur is converted into a modification soluble in water, viz: sodium hyposulfite.

For the purpose of dehydrating the filaments and rendering them firmer and less liable to abrasion during .the subsequent finishing process than if treated solely with the setting-bath of sodium bisulfite aforesaid I find it advantageous to add a saline solution to said bath. For instance, I make a bath.

of saturated aqueous solution of acid soe dium sulfite containing from eleven andonehalf to twelve per cent. of availablesulfurous f acid and to, this add ten percent. of its weight of a saturated solution of ammonium sulfate sodium chlorid or other similar dehydrating agent. The setting-bath aforesaid should preferably be heated to about centigrade, and aftertreatment therein I- subject said products to the action of steam in the presence'of the-residual sulfurous acid, the steaming process being continued for from one to two hours, according to the thickness of the products. *The products may advanta eousl be lacedu on tension g y P P during the steammg process", and after steaming it is only necessary to wash said products and dry them. I I v The'reactions due to the treatment above described may be assumed to be as follows:

'The viscose compound is decomposed by heat. The sulfur contained therein is transformed into. sodium hyposulfite, and the so- The process above described is particu-.

larly valuable in the production of very fine filaments of lustra-c'ellulose or artificial silk, where a number of such filaments are to be spun together to form com osite threads. In this case any residual SOdlIllIl hydrate tends to redissolve the surfaces of the individual filaments and agglomerate them, impairing the luster, softness, and pliability of the composite threads.

Having thus described my invention, I

1. The hereinbefore-described process of making viscose products, which consists in subjecting liquid'viscose to the action of a solution comprising sodium bisulfite; and, then making viscose products which consists .in eliminating such residual constituents as sulinitiallysubjecting liquid viscose to the acfur and sodium. hydrate, by steaming said tion of a coagulating solution comprising soproducts in the presence of sulfurous acid, dium bisulfite; and, then eliminating such 20 5 substantially as set forth. residual constituents as sulfur and sodium 2. The hereinbefore-described process of hydrate, by steaming said products in the making viscose products, which consists in presence of sulfurous acid, substantially as subjecting liquidviscose to the action of a soset forth. c lution comprising sodium bisulfite; then In Witness whereof I have hereunto signed 25 IO eliminating such residual constituents as sulany name, at Philadelphia, in the State of fur (iind'sodiulrlnhydrate, bty siiifaaming said Pennsylvania, this 2d day of May, 1904.

r0 nets. in t e presence 0' sn urous aci 2nd, subjecting said products to tension dur- CHARLES WAITE ing the steaming process, substantally as set Witnesses: 15 forth. a ARTHU'R E. PAIGE,

3. The hereinbefore-described process of ANNA F. GETZFREAD. 

